Portable coolers for use in keeping beverage containers and prepackaged beverages at a chilled temperature are known. Many portable coolers consist of a small ice chest made from an insulative material which separates an interior volume from the relatively warm ambient surroundings (i.e., air). Ice--or reusable ice substitutes--and the beverage containers are placed inside the ice chest. The interior volume of the cooler is cooled to a temperature substantially below that of the ambient air and approaches the temperature of the melting ice. However, air is a poor conductor of heat and the transfer of heat energy from the beverage containers is inefficient. The insulative material helps to maintain this lower temperature for an extended period of time thereby keeping the beverages at a desired drinking temperature.
The reusable ice substitutes (sometimes referred to as freeze-packs) are hollow plastic containers filled with a refrigerant. The refrigerant may be a liquid (e.g., water, salt water, etc.) or a gel-like substance. The refrigerant becomes solid when placed in a freezer. The reusable ice substitutes are sometimes designed with scallops to accommodate beverage containers. The scalloped reusable ice substitutes help in resisting movement of the beverage containers within the interior volume of the cooler. However, the utilization of these reusable ice substitutes in portable coolers tends to make the cooler awkward and bulky. In addition, they may decrease the accessibility or removability of the beverage containers from the cooler.